RESEARCH INSTITUTE FOR CEREALS AND INDUSTRIAL CROPS - I.C.C.P.T.
Fundulea, 8264, jud. Calarasi, Romania.
Dark-induced senescence in seedlings is correlated with flag leaf senescence in the field.
N.N. Sãulescu and P. Mustãtea.
We previously identified large genotypic differences among wheat cultivars for dark-induced senescence in seedlings (AWN Vol. 44). Recent data show that a good correlation exists between the rate of dark-induced chlorophyll loss in seedlings and the rate of age-induced senescence of flag leaves in the field in the absence of disease. Slow senescence seems to be a characteristic of cultivars adapted to more favorable environments (e.g., west European cultivars), whereas fast senescence can be found in cultivars that are more adapted to stressed environments (e.g., U.S. cultivars Karl and Jagger). The seedling test for dark-induced senescence could facilitate selection for the optimum senescence pattern suitable for the target environment.
Genetic progress in Fundulea triticale breeding program.
G. Ittu, N.N. Sãulescu, and Mariana Ittu.
Genetic gain for yield and other agronomic characteristics were evaluated in yield trials for 2 years at 10 locations in the hilly regions. Four triticale cultivars (TF 2, Plai, Colina, and Titan) bred in Romania from 1984 to 1998 were tested. The genetic gain for yield was estimated at 96.03 kg/ha/year. A more or less similar genetic gain was reported in two triticale breeding programs, the CIMMYT spring triticale and the Polish winter triticale breeding programs. Yield improvement resulted from an increase in the number of kernels/spike (0.4 kernels/year), weight of kernels/spike (0.0164 g/year), and test weight (0.337 kg/hl/year). Average plant height decreased from 128.5 to 114 cm (-0.871 cm/year ), with a favorable effect on lodging resistance. Interestingly, yield increases were associated with earlier heading times (-3 days).
S.C.A.-AGRICULTURAL RESEARCH STATION
Turda, 3350, str. Agriculturii 27 Jud Cluj, Romania.
Breeding priorities of the winter wheat program at Agricultural Research Station, Turda.
V. Moldovan, Maria Moldovan, and Rozalia Kadar.
A large part of Romania's wheat yield is produced in Transylvania, where environmental conditions are variable and highly unpredictable. The climate of Transylvania is continental. Winters can be highly variable, and low temperatures frequently may occur without snow cover. Spring and summer temperatures fluctuate widely, and precipitation is unpredictable and can range from less than 350 mm to more than 700 mm annually. Foliar and spike diseases occur annually in Transylvania and can have a great distructive potential and quantitatively and qualitatively depreciate wheat yields. To be acceptable to producers, wheat cultivars must tolerate these conditions and respond to favorable farming conditions with good performance.
Winter wheat breeding priorities at ARS Turda, which is located in the heart of Transylvania, are largely dictated by the problems of wheat production in this region. The following objectives are emphasised in our wheat breeding program:
1. yield and performance stability,
2. bread-making and nutritional quality,
3. disease resistance,with emphasis on Fusarium,
4. winter hardiness, and
5. lodging resistance.
Numerous additional traits such as earliness, plant height, foliar disease resistance, sprouting resistance, tillering, seed size, test weight, and harvest index are monitored. Each contributes to the performance and acceptability of new cultivars.
Some aspects of the stability of response of wheat to Fusarium head blight.
Maria Moldovan and V. Moldovan.
Fusarium head blight is one of the most important diseases
of wheat, because it decreases grain yield and deteriorates grain
quality. Two studies conducted between 1994-97 determined the
factors that influence the response of wheat to FHB. A group of
34 winter wheat genotypes of different origins was tested under
artificial infection with F. graminearum in the field at
the ARS in Turda. In 1997, 42 winter wheat genotypes were tested
with four isolates from local population of F. graminearum.
In both experiments, 10 spikes/entry were inoculated at anthesis
by injecting two spikelets with one drop of inoculum (a suspension
of F. graminearum conidia and mycelium in liquid Czapek-Dox
medium). An equal number of uninoculated spikes (control) were
harvested. The FHB reaction was evaluated as the rate of infection
(%) at 20 days after inoculation (percent of diseased spikelets
was calculated for each spike and the data for 10 spikes were
averaged). The relative weight of the spikes was evaluated for
each entry (compared to the control).
FHB reduced the weight of the spike by 44.8 % (in 42 genotypes, mean is for 2 years). Results in each of the 4 years of the first experiment were significantly different (P = 5 %). Isolates of the second experiment differed in pathogenicity. The response of wheat to FHB was significantly influenced by the genotype and year (Table 1) and isolate (Table 2).
| Source of variation | d.f. | MS | F | Contribution of the factors (%) |
|---|---|---|---|---|
| Genotypes | 33 | 814.87 | 5.44 (1.89) * | 37.37 |
| Years | 3 | 5,731.41 | 38.29 (3.98) * | 28.43 |
| Within | 99 | 149.67 | 34.30 | |
| Total | 135 | 436.31 | 100.00 | |
| * Limit of F value for P = 0.01. | ||||
| Source of variation | d.f. | MS | F | Contribution of the factors (%) |
|---|---|---|---|---|
| Genotypes | 41 | 1,043.31 | 6.79 (2.11) * | 42.81 |
| Years | 3 | 7,849.93 | 51.13 (3.98) * | 27.10 |
| Within | 123 | 153.52 | 30.09 | |
| Total | 167 | 510.23 | 100.00 | |
| * Limit of F value for P = 0.01. | ||||
The heritability was H = 37.3 %. Despite the large influence of the environment, genotype also made an important contribution in the response to FHB. Variation in the reaction was very high. The response of the 34 wheat genotypes to the intensity of FHB attack ranged between 25.0 % and 96.2 % (mean of 4 years).
The stability of the reaction to FBH was low, with a coefficient of variation between 10.1 % and 49.8 %. Therefore, to be sure of the value of a genotype as a possible source of resistance to FHB, its reaction must be tested in many environments (year or/and localities) and with a highly pathogenic isolate.
These two experiments confirmed the value of some genotypes as possible sources of resistance to FHB. The promising genotypes are Fundulea 20-1-R, Fundulea 5168-W1, Turda 45-85, FT 11793-91, FT 12653-91, Fundulea 483 P-5,Fundulea 4549 W 2, Fundulea 116, FT 11403-91, Turda 50-93, Turda 107-93, Turda 2362-93, and Turda 2826-90, plus Bizel-Zenith 53 from France.
Varietal and environmental effects on bread-making quality in winter wheat.
Rozalia Kadar and V. Moldovan.
Eight winter wheat cultivars created in Romania (Fundulea 4, Fundulea 29, Turda 81, Transilvania, Ariesan, Apullum, Turda 95, and Flamura 85) were tested in wheat trials at ARS, Turda, and their bread-making qualities determined over a 5-year period (1992-97). Quality parameters analyzed were protein content, wet-gluten content, sedimentation value, deformation index, and loaf volume.
The genotypic and environmental effects on these quality parameters were measured by various analyses using a statistical model that allows for a percentage separation of genotype and environment effects in phenotypic characters and an estimation of a broad-sense heritability coefficient.
| Characteristic | Share | Heritability coefficient (broad sense) | F-test * | |||
|---|---|---|---|---|---|---|
| Genotype | Environment | G x E | Genotype | Environment | ||
| Protein content | 39.47 | 16.83 | 43.70 | 0.37 | ** | NS |
| Wet gluten content % | 69.57 | 12.76 | 17.67 | 0.66 | ** | ** |
| Sedimentation index (ml) | 89.98 | 0.28 | 9.73 | 0.89 | ** | NS |
| Deformation index (mm) | 53.00 | 2.00 | 45.00 | 0.52 | ** | NS |
| Loaf volume (cmc) | 59.81 | 0.77 | 39.42 | 0.58 | ** | NS |
| * ** significant at P = 0.01; NS = not significant | ||||||
Data for the quality parameters analyzed are in Table 3. Protein content had a phenotypic expression that was influenced by environment conditions and a "G x E' interaction. Sedimentation value best explained protein quality. For wet gluten, the deformation index expressed quality. The index for protein quality (sedimentation value) and that of gluten quality (deformation index) were influenced by genotype more than environment, and the F-tests were significant at P = 0.01.